Definitely varies. People have abused the crap out of Walmart's policy especially with "van life" going super viral on social media and drug addiction continuing to be a huge problem for our state.
The two Walmarts near me (Worcester County) have posted signs banning overnight parking. Both locations have had lots of trouble with drug addicts, theft, robberies, etc. The one in Worcester had so many addicts living in the lot, it was kind of scary. Now they all live in the woods behind the store.
ThrillDr1 t1_j290xwq wrote
I believe Walmart allows people to park overnight in their lots.